nixos: fix qemu_test being used in normal VMs

[rnhmjoj]

Motivation for this change

It looks like since PR #49403 the VMs built by nixos-rebuild built-vm are using the stripped-down qemu package, which lacks gtk and spice support.

Things done

• Tested that nixosTests uses qemu_test package
• Tested that build-vm uses the normal qemu package
• Test I have not broken more things by removing config.system.build.qemu

[andir]

I just wrote a very similar patch before I found this.

We should probably add a virtualisation.qemu.package = pkgs.qemu_test; line to nixos/modules/testing/test-instrumentation.nix to ensure the tests are still using that.

Otherwise it looks fine. I haven't executed this code yet tho..

[rnhmjoj]

We should probably add a virtualisation.qemu.package = pkgs.qemu_test; line to nixos/modules/testing/test-instrumentation.nix to ensure the tests are still using that.

Wait, isn't this exactly what I'm doing in this PR?

[andir]

We should probably add a virtualisation.qemu.package = pkgs.qemu_test; line to nixos/modules/testing/test-instrumentation.nix to ensure the tests are still using that.

Wait, isn't this exactly what I'm doing in this PR?

Yes, sorry. The line breaking on the (small) GitHub Window didn't really make that obvious. It looked more like you did just reflow some of the code but indeed you are doing exactly that. :)

[andir]

* [ ]  Test I have not broken more things by removing `config.system.build.qemu`

There is one case of system.build.qemu in nixos/lib/build-vms.nix.

[rnhmjoj]

Thank you, I'll take a look at build-vms now.

[rnhmjoj]

It looks like that line can simply be removed, since the test package is already being configured by test-instrumentation.

[andir]

I am building all the tests over night and will merge this in the morning when everything looks fine.

[xaverdh]

Ah so I think this pr reintroduced the eval error which was supposed to be fixed by rnhmjoj@2578557#diff-ec9255f81e919804497f4a2ae13abd965816f4c519b08d037be851055ac53b4e ?